Process for the preparation of ring compounds

ABSTRACT

In a process for the preparation of ring compounds via a combinatorial synthesis, the reaction procedure is based on a Suzuki coupling, subsequent halo-demetallation and finally a further Suzuki coupling. The Suzuki couplings are each carried out with a boronic acid or a boronic acid ester. The reaction procedure uses provides novel ring compounds and uses novel synthesis units used for this purpose. The novel ring compounds are suitable for use as constituents in liquid-crystalline mixtures.

The present invention relates to a process for the preparation of ringcompounds via a combinatorial synthesis based on a Suzuki coupling,subsequent halo-demetallation and finally a Suzuki coupling. The Suzukicouplings are each carried out with a boronic acid or a boronic acidester. The present invention likewise relates to the corresponding ringcompounds and to the novel synthesis units used for this purpose. Thering compounds according to the invention are preferably used asconstituents in liquid-crystalline mixtures.

The prior art discloses the palladium-catalysed cross-coupling reactionof aromatic boron compounds, such as boronic acids and derivativesthereof, and aromatic halogen compounds (EP 0 470 795 A1), which has forsome years also increasingly been used in the area of organic synthesis.The process described in EP 0 470 795 A1 is based on a homogeneouslycatalysed process using palladium(0) complexes, in particulartetrakis-(triphenylphosphine)palladium(0). It is disadvantageous in thisprocess that the complexes are oxidation-sensitive, causing them to loseactivity. Owing to the varying activity, the process is difficult toreproduce and the yields are in some cases very low. In addition, thecomplexes are very expensive.

DE 44 26 671 A1 discloses a process for the preparation of polycyclicaromatic compounds by cross-coupling aromatic boron compounds witharomatic halogen compounds or perfluoroalkyl sulfonates with palladiumcatalysis in the presence of at least one water-soluble complex ligand.This process is carried out with a 2-phase system comprising an organicphase and an aqueous phase, with the palladium catalyst being dissolvedin the organic phase. It is disadvantageous in this process that verygood mixing of the two phases is a prerequisite for the reaction. Inaddition, this process is also very expensive owing to the catalystsemployed.

Starting from this prior art, an object of the present invention is toprovide a process or to develop a combinatorial synthesis strategy withwhich products can be obtained in high yield and high conversion with asmall number of reaction steps.

Upon further study of the specification and appended claims, furtherobjects and advantages of this invention will become apparent to thoseskilled in the art.

These objects are achieved in accordance with the invention by a processcomprising subjecting a compound of formulae V to VIII

-   -   wherein    -   Z is I, Cl, Br or triflate,    -   M is Si, Ge or Sn, and    -   R³, R⁴ and R⁵, independently of one another, are identical or        different and are each H, C₁-C₁₂-alkyl or C₁-C₁₂-alkoxy,        via combinatorial synthesis, to the following reaction steps        which are carried out in a matrix-like arrangement of reaction        vessels:    -   A) Suzuki coupling with a boronic acid or a boronic acid ester        of formula X

-   -   -   wherein        -   R⁶ and R⁷, independently of one another, are identical or            different and are each H, C₁-C₁₂-alkyl, C₂-C₁₂-alkenyl or            aryl, and where R⁶ and R⁷ can also be bridged in a cyclic            manner;

    -   B) subsequent halo-demetallation; and

    -   C) Suzuki coupling with a boronic acid or a boronic acid ester        of formula XI

-   -   wherein one or two CH groups in the aromatic ring systems of        formulae V to VIII, X and XI may each also be replaced by N.

The invention further relates to liquid-crystalline ring compounds offormula XIII

-   -   wherein    -   one or two CH groups in the aromatic ring systems of formula        XIII may each be replaced by N;    -   Y is a group of formulae XIV to XVII

-   -   in which one or two CH groups in the aromatic ring systems may        each be replaced by N;    -   m and n, independently of one another, are identical or        different and are each 0 or 1, and the sum m+n is 1 or 2;    -   X is a single bond, —CH₂—CH₂—, —CH═CH—, —C≡C— or

-   -   L, independently of one another, are identical or different and        are each R, F, Cl, Br, I, OH, OR, SH, SR, CN, NO₂, NO, CHO,        COOH, COOR, CONH₂, CONHR, CONR₂, CF₃, NH₂, NHR or NR₂;    -   R is an alkyl, alkenyl or acyl group having up to 12 carbon        atoms or an aryl group having 6 carbon atoms which is optionally        substituted by an alkyl group having from 1 to 12 carbon atoms;        and    -   a, b, c, d, e and f, independently of one another, are identical        or different and are each 0, 1 or 2, and the sum a+b+c+d+e+f is        1 to 8, preferably 3 to 8;    -   R¹ and R², independently of one another, are identical or        different and are each H, F, Cl, CN, NCS, a straight-chain or        branched, optionally chiral alkyl radical or alkoxy radical        having from 1 to 12 carbon atoms or an alkenyl radical or        alkynyl radical having from 2 to 8 carbon atoms, in each of        which, in addition, one CH₂ group may be replaced by —O—, —CO—,        —O—CO—, —COO— or —CH═CH— in such a way that heteroatoms are not        linked directly to one another and/or one or more H may be        replaced by halogen, preferably F; and    -   in the case where m is 0 or n is 0, one CH₂ group in R¹ or R²        may be replaced by one of the following groups:    -   a) trans-1,4-cyclohexylene, in which, in addition, one or more        non-adjacent CH₂ groups may each be replaced by —O— or —S—,    -   b) a radical from the group consisting of        1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,        naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and        1,2,3,4-tetrahydronaphthalene-2,6-diyl, or    -   c) 1,4-cyclohexenylene,        and in which the radicals a), b) and c) may also be substituted        by CN and/or halogen.

In accordance with a further aspect of the invention there are provideboronic acids or boronic acid ester compounds as synthesis units,including;

boronic acid or boronic acid ester compounds of formula XIX

-   -   wherein    -   one or two CH groups in the aromatic ring system may each be        replaced by N;    -   r is 1 or 2;    -   R is H, F, Cl, CN, NCS, a straight-chain or branched, optionally        chiral, alkyl radical or alkoxy radical having from 1 to 12        carbon atoms or an alkenyl radical or alkynyl radical having        from 2 to 8 carbon atoms, in each of which, in addition, one CH₂        group may be replaced by —O—, —CO—, —O—CO— or —COO— in such a        way that heteroatoms are not linked directly to one another        and/or one or more H may be replaced by halogen;    -   the L groups, independently of one another, are identical or        different and are each R′, F, Cl, Br, I, OH, OR, SH, SR′, CN,        NO₂, NO, CHO, COOH, COOR′, CONH₂, CONHR′, CONR₁₂, CF₃, NH₂, NHR′        or NR′₂;    -   R′ is an alkyl, alkenyl or acyl group having from up to 12        carbon atoms or an aryl group having 6 carbon atoms, which is        optionally substituted by an alkyl group having from 1 to 12        carbon atoms;    -   a, is 0, or 2;    -   R⁶ and R⁷, independently of one another, are identical or        different and are each H, C₁-C₁₂-alkyl, C₂-C₁₂-alkenyl or aryl,        and where R⁶ and R⁷ can also be bridged in a cyclic manner; and        boronic acid or boronic acid ester compound of formula XXI

-   -   wherein    -   one or two CH groups in the aromatic ring system may each be        replaced by N;    -   r is 1 or 2;    -   R³, R⁴ and R⁵, independently of one another, are identical or        different and are each H, C₁-C₁₂-alkyl or C₁-C₁₂-alkoxy;    -   R⁶ and R⁷, independently of one another, are identical or        different and are each H, C₁-C₁₂-alkyl, C₂-C₁₂-alkenyl or aryl,        and where R⁶ and R⁷ can also be bridged in a cyclic manner;    -   M is Si, Ge or Sn;    -   the L groups, independently of one another, are identical or        different and are each R′, F, Cl, Br, I, OH, OR′, SH, SR′, CN,        NO₂, NO, CHO, COOH, COOR′, CONH₂, CONHR′, CONR′₂, CF₃, NH₂, NHR′        or NR′₂;    -   R′ is an alkyl, alkenyl or acyl group having from up to 12        carbon atoms or an aryl group having 6 carbon atoms, which is        optionally substituted by an alkyl group having from 1 to 12        carbon atoms; and    -   a, is 0, 1 or 2.

In accordance with the invention, a process is provided for thepreparation of ring compounds of the general formulae I to IV

In these formulae, m and n, independently of one another, are identicalor different and can adopt the values 0 or 1, where the sum (m+n) is 1or 2. Particularly preferably, m=n=1, i.e. the sum (m+n)=2.

X is a single bond, —CH₂—CH₂—, —CH═CH—, —C≡C— or

X is preferably a single bond.

The L groups, independently of one another, are identical or differentand are each R, F, Cl, Br, I, OH, OR, SH, SR, CN, NO₂, NO, CHO, COOH,COOR, CONH₂, CONHR, CONR₂, CF₃, NH₂, NHR or NR₂, where R is an alkyl,alkenyl or acyl group having from 1 to 12 carbon atoms or an aryl grouphaving 6 carbon atoms, which may, if desired, in turn be substituted byan alkyl group having from 1 to 12 carbon atoms. The L groups arepreferably, independently of one another, identical or different, andare each F, Cl, CF₃ or CH₃, where F is particularly preferred.

The indices a, b, c, d, e and f may, independently of one another, beidentical or different and adopt the values 0, 1 or 2, where the suma+b+c+d+e+f adopts values between 1 and 8, preferably between 3 and 8and particularly preferably between 4 and 8. One or two CH groups in thearomatic ring systems of the formulae I to IV may each be replaced by N.

R¹ and R², independently of one another, are identical or different andare H, F, Cl, CN or NCS. It is likewise possible for R¹ and/or R² to bea straight-chain or branched, optionally chiral alkyl radical or alkoxyradical having from 1 to 12 carbon atoms or an alkenyl radical oralkynyl radical having from 2 to 8 carbon atoms, where one CH₂ group ineach of these organic radicals may also be replaced by —O—, —CO—, —O—CO—or —COO— in such a way that heteroatoms are not linked directly to oneanother and/or one or more H may be replaced by halogen, preferably F.R¹ and/or R² are preferably a straight-chain alkyl radical having from 1to 7 carbon atoms. In a further preferred embodiment, R² is a chiralalkyl radical having from 1 to 12 carbon atoms.

In the case where m=0 or n=0, one CH₂ group in R¹ or R² is preferablyreplaced by one of the following groups:

-   a) trans-1,4-cyclohexylene, in which, in addition, one or more    non-adjacent CH₂ groups may each be replaced by —O— or —S—,-   b) a radical from the group consisting of    1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,    naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and    1,2,3,4-tetrahydronaphthalene-2,6-diyl, or-   c) 1,4-cyclohexenylene.

The radicals a), b) and c) may also be substituted by CN and/or halogen.

If R¹ and/or R² in the formulae above and below are an alkyl radical,this may be straight-chain or branched. It is particularly preferablystraight-chain, has 1, 2, 3, 4, 5, 6 or 7 carbon atoms and isaccordingly methyl, ethyl, propyl, butyl, pentyl, hexyl or heptyl,furthermore octyl, nonyl, decyl, undecyl or dodecyl.

If R¹ and/or R² are an alkyl radical in which one CH₂ group has beenreplaced by —O—, this may be straight-chain or branched. It ispreferably straight-chain and has from 1 to 10 carbon atoms. The firstCH₂ group in this alkyl radical is particularly preferably replaced by—O—, so that the radical R¹ attains the meaning alkoxy and is methoxy,ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy ornonyloxy.

It is furthermore also possible for a CH₂ group elsewhere to be replacedby —O—, so that the radical R¹ and/or R² is preferably straight-chain2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or 3-oxabutyl(=2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-,3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-,5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R¹ and/or R² are an alkyl radical in which one CH₂ group has beenreplaced by —O— and one has been replaced by —CO—, these are adjacent.These thus contain an acyloxy group —CO—O— or an oxycarbonyl group—O—CO—. These are particularly preferably straight-chain and have from 2to 6 carbon atoms.

Accordingly, they are in particular acetoxy, propionyloxy, butyryloxy,pentanoyloxy, hexanoyloxy, acetoxymethyl, propionyloxymethyl,butyryl-oxymethyl, pentanoyloxymethyl, 2-acetoxyethyl,2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetoxypropyl,3-propionyloxypropyl, 4-acetoxybutyl, methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl,ethoxycarbonylmethyl, propoxy-carbonylmethyl, butoxycarbonylmethyl,2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl,2-(propoxycarbonyl)ethyl, 3-(methoxycarbonyl)-propyl,3-(ethoxycarbonyl)propyl and 4-(methoxycarbonyl)butyl.

If R¹ and/or R² are an alkyl or alkenyl radical which is monosubstitutedby CN or CF₃, this radical is preferably straight-chain and thesubstitution by CN or CF₃ is in the co-position.

If R¹ and/or R² are an alkyl radical which is at least monosubstitutedby halogen, this radical is preferably straight-chain. Halogen ispreferably F or Cl. In the case of polysubstitution, halogen ispreferably F. The resultant radicals also include perfluorinatedradicals. In the case of monosubstitution, the fluorine or chlorinesubstituent can be in any desired position, but preferably in theω-position.

Compounds of the formula I having a branched wing group R¹ and/or R² mayoccasionally be of importance owing to better solubility in theconventional liquid-crystalline base materials, but in particular aschiral dopants if they are optically active. Smectic compounds of thistype are suitable as components of ferroelectric materials.

Branched groups of this type generally contain not more than one chainbranch. Preferred branched radicals R¹ and/or R² are isopropyl, 2-butyl(=1-methylpropyl), isobutyl (=2-methylpropyl), 2-methylbutyl, isopentyl(3-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl,2-propyl-pentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy,3-methylbutoxy, 2-methylpentyloxy, 3-methylpentyloxy, 2-ethylhexyloxy,1-methylhexyloxy and 1-methylheptyloxy.

The groups m, n, X, L, a, b, c, d, e, f, R^(t) and R² below are asdefined above unless expressly stated otherwise. Correspondingly, one ortwo CH groups in the ring systems mentioned below may also each bereplaced by N analogously to the ring compounds of the general formulaeI to IV.

The ring compounds of the general formulae I to IV are prepared startingfrom the compounds of the formulae V to VIII:

Z here is selected from the group consisting of I, Cl, Br and OTf(triflate), where Z is preferably I, and M is selected from the groupconsisting of Si, Ge and Sn, where Si is preferred.

R³, R⁴ and R⁵, independently of one another, are identical or differentand are H, C₁-C₁₂-alkyl or C₁-C₁₂-alkoxy.

Furthermore, at least one of the radicals R³, R⁴ and R⁵ in the generalformulae V to VIII can be a fluorine-containing alkyl radical of thegeneral formula IX

—(CH₂)_(p)—(CF₂)_(q)—CF₃  IX

where p can adopt values in the range from 2 to 4, q can adopt values≧2, and the sum (p+q) can adopt values in the range from 2 to 11. q ispreferably >p.

R³, R⁴, R⁵, M and Z below are as defined above unless expressly statedotherwise.

The ring compounds are prepared via combinatorial synthesis, in whichthe following reaction steps are carried out in a matrix-likearrangement of reaction vessels:

-   A) Suzuki coupling with a boronic acid or a boronic acid ester,    preferably a boronic acid ester, of the general formula X

-   -   where R⁶ and R⁷, independently of one another, are identical or        different and are H, C₁-C₁₂-alkyl, C₂-C₁₂-alkenyl, preferably        C₃-C₁₂-alkenyl, or C₆₋₁₀-aryl (preferably C₆-aryl). R⁶ and R⁷        may also be bridged in a cyclic manner.    -   R⁶ and R⁷ below are as defined above unless expressly stated        otherwise.

-   B) subsequent halo-demetallation, preferably iodo-desilylation, and

-   C) Suzuki coupling with a boronic acid or a boronic acid ester,    preferably a boronic acid ester, of the general formula XI

In a step preceding step A), the compound of the formula V, in which Xis a single bond, is preferably prepared from a boronic acid or aboronic acid ester of the formula XII

by Suzuki coupling with an at least partially fluorinatedp-bromoiodo-benzene, which is carried out as a combinatorial synthesisin a matrix-like arrangement of reaction vessels, with a subsequentiodination step for substitution of the bromine, for example by means ofbutyllithium and an iodinating agent.

A particular advantage of the process according to the invention is thatthis is carried out as a combinatorial synthesis. For the development ofcombinatorial synthesis, it is necessary to develop a synthesis conceptwith reactions matched to one another, with the aim being to optimisethe reactions with respect to conversion and yield. The process iscarried out as a divergent synthesis, which has the advantage over alinear synthesis that only three reaction steps are needed. Linearsynthesis, by contrast, would require five reaction steps. A furtheradvantage is the smaller purification effort compared with theperformance of a linear synthetic process.

The intermediates and/or end products are preferably purified byrecrystallisation, and the crystals are isolated via cartridges forsolid-phase extraction, with the purification being carried out inparallel for all reaction vessels.

Regarding the Suzuki couplings, the base needed for this purpose ispreferably selected from the group consisting of the hydroxides,carbonates and fluorides, with barium hydroxide and caesium fluoridebeing particularly preferred.

The catalyst employed is preferably a palladium-containing compound,particularly preferably palladium acetate.

The reaction is preferably carried out in a polar solvent, such as, forexample, an alcohol or ether. Particular preference is given here to theuse of isopropanol.

In a further particularly preferred variant of the Suzuki coupling, thebase employed is caesium fluoride, the catalyst employed is palladiumacetate, and the solvent employed is dioxane.

The preferred Suzuki coupling variants described here have the advantagethat virtually quantitative conversion is achieved and the product isfree from palladium. At the same time, no by-products which cannot beseparated off are formed, meaning that the purity of the crude productsis adequate for the subsequent reactions. Further advantages of thiscatalyst are its simple handling, its stability in air and its lowprice.

The Suzuki couplings are preferably carried out at a temperature between10 and 120° C. and a reaction duration between 0.1 and 30 hours.Particular preference is given to temperatures between 50 and 100° C.and a reaction duration between 18 and 24 hours.

The iodo-desilylation, as the preferred variant of thehalo-demetallation, is preferably carried out with addition of iodinechloride in methyl cyanide, Temperatures between 10 and 75° C. and areaction duration between 0.1 and 20 hours are preferably observed here.Particular preference is given to temperatures between 20 and 30° C. anda reaction duration between 0.5 and 2 hours.

An important step in the synthesis is suppression of side-chainchlorinations during the halo-demetallation. This side-chainchlorination of the radicals R¹ and R² can be prevented virtuallycompletely if an iodo-desilylation is carried out in acetonitrile. Afurther reason for the preference for iodo-desilylation in combinationwith the Suzuki coupling is its compatibility with respect to fluorinesubstituents in the opposition.

The process according to the invention for the preparation of ringcompounds of the general formulae I to IV is shown in detaileddiagrammatic form below for the preferred ring compounds of the generalformula XVIII.

The preparation of the biphenyl, the starting substance of the processaccording to the invention, is shown in scheme 1. Scheme 2 shows thesynthesis of the terphenyl starting from the biphenyl from scheme 1 anda boronic acid (step A of the process according to the invention).Scheme 3 describes the iodo-desilylation of the terphenyl from scheme 2(step B of the process according to the invention), and scheme 4describes the synthesis of the quaterphenyl (step C of the processaccording to the invention).

Ring compounds of the general formula XIII

where m and n, independently of one another, are identical or differentand adopt the value 0 or 1, where the sum (m+n) is 1 or 2, preferablym=n=1, i.e. the sum (m+n)=2, are likewise prepared in accordance withthe invention.

Y here is a group of the general formulae XIV to XVII

where X single bond, —CH═CH—, —C≡C— or

L, independently of one another, are identical or different and are R,F, Cl, Br, I, OH, OR, SH, SR′, CN, NO₂, NO, CHO, COOH, COOR, CONH₂,CONHR, CONR₂, CF₃, NH₂, NHR or NR₂, where R is an alkyl, alkenyl or acylgroup having from 1 to 12 carbon atoms or an aryl group having 6 carbonatoms, which may, if desired, in turn be substituted by an alkyl grouphaving from 1 to 12 carbon atoms. L are preferably, independently of oneanother, identical or different, and are F, Cl, CF₃ or CH₃, where F isparticularly preferred.

The indices a, b, c, d, e and f may, independently of one another, beidentical or different and adopt the values 0, 1 or 2, where the sum(a+b+c+d+e+f) adopts values between 1 and 8, preferably between 3 and 8and particularly preferably between 4 and 8. One or two CH groups in thearomatic ring systems of the formulae XIII to XVII may each be replacedby N.

R¹ and R², independently of one another, are identical or different andare H, F, Cl, CN or NCS. It is likewise possible for R¹ and/or R² to bea straight-chain or branched, optionally chiral alkyl radical or alkoxyradical having from 1 to 12 carbon atoms or an alkenyl radical oralkynyl radical having from 2 to 8 carbon atoms, where one CH₂ group ineach of these organic radicals may also be replaced by —O—, —CO—,—O—CO—, —COO— or —CH═CH— in such a way that heteroatoms are not linkeddirectly to one another and/or one or more H may each be replaced byhalogen, preferably F.

In the case where m=0 or n=0, one CH₂ group in R¹ or R² must be replacedby one of the following groups:

-   a) trans-1,4-cyclohexylene, in which, in addition, one or more    non-adjacent CH₂ groups may each be replaced by —O— or —S—,-   b) a radical from the group consisting of    1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,    naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and    1,2,3,4-tetrahydronaphthalene-2,6-diyl, or-   c) 1,4-cyclohexenylene.

The radicals a), b) and c) here may also be substituted by CN and/orhalogen.

Preference is given to ring compounds of the general formula XVIII

where particularly preferably m=n=1, and the radicals R¹ and R²,independently of one another, are identical or different and areselected from the group C₁-C₇-alkyl.

Particular preference is given here to ring compounds of the followingformulae XVIIIa to XVIIIg:

where R¹ and R² are as defined above in respect of formula XVIII, L¹, L²and L³ can adopt the meanings of L^(d), and L⁴, L⁵ and L⁶ can adopt themeanings of L^(a). Particular preference is given here to the ringcompounds of the formulae XVIIIf and XVIIIg.

Boronic acids or boronic acid esters of the general formula XIX

are also prepared in accordance with the invention as synthesis units.

The boronic acids or boronic acid esters preferably have a structure inaccordance with the general formula XX

In the structures XIX and XX, r can be m or n and can thus adopt thevalues 1 or 2, preferably 1. If r=m, then R═R¹, and if r=n, then R═R².

R can be as defined for R¹ and R² and is thus H, F, Cl, CN or NCS.

It is likewise possible for R to be a straight-chain or branched,optionally chiral alkyl radical or alkoxy radical having from 1 to 12carbon atoms or an alkenyl radical or alkynyl radical having from 2 to 8carbon atoms, where one CH₂ group in this organic radical may also bereplaced by —O— or —COO— in such a way that heteroatoms are not linkeddirectly to one another and/or one or more H may each be replaced by F.In addition, in the case where r=0, one CH₂ group in R may also bereplaced by one of the following groups:

-   a) trans-1,4-cyclohexylene, in which, in addition, one or more    non-adjacent CH₂ groups may each be replaced by —O— or —S—,-   b) a radical from the group consisting of    1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,    naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and    1,2,3,4-tetrahydronaphthalene-2,6-diyl, or-   c) 1,4-cyclohexenylene.

R⁶, R⁷, L and a here are as defined above.

R⁸ and R⁹, independently of one another, are identical or different andare C₁-C₁₂-alkyl or C₆₋₁₀-aryl (preferably C₆-aryl).

Furthermore, boronic acids or boronic acid esters of the general formulaXXI

are prepared in accordance with the invention.

The boronic acids or boronic acid esters preferably have the generalformula XXII

M, r, R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, L and a here are as defined above.

One or two CH groups in the aromatic ring systems of the generalformulae XIX, XX, XXI and XXII may likewise each be replaced by N.

The entire disclosure of all applications, patents and publications,cited above and below, and of corresponding German Application No.10211597.4, filed Mar. 15, 2002, is hereby incorporated by reference.

The invention is described in greater detail below with reference toworking examples, in which illustrative compounds according to theinvention are mentioned which have been prepared by combinatorialsynthesis, but without in any way being restricted thereby.

Above and below, percentages are percent by weight.

At the same time, these compounds have been characterised with referenceto their phase transitions.

C denotes crystalline state, N=nematic phase, Sm=smectic phase andI=isotropic phase. The data between these symbols are the transitiontemperatures. All temperatures are given in degrees Celsius.

EXAMPLE 1 Preparation of the Boronic Acid (4)

4-Bromo-2,6-difluorobenzaldehyde (1)

55 ml (0.11 mmol) of 2 M lithium diisopropylamide are added withstirring at −70° C. to a solution of 19.3 g (0.1 mmol) of1-bromo-3,5-difluorobenzene in 120 ml of dried tetrahydrofuran. After 30minutes, N-formylpiperidine is added dropwise at this temperature. Themixture is allowed to warm to 0° C. At about 0° C., the reaction mixtureis poured into cold water, acidified using 10% HCl and extracted twicewith methyl tert-butyl ether. The combined organic phases are washedwith water, dried over Na₂SO₄ and filtered, and the solvent is removedunder reduced pressure. The residue is filtered through SiO₂(heptane/dichloromethane 1:1), (yield: 17.6 g, 78%).

5-Bromo-1,3-difluoro-2-[(R)-3-methylpent-1-enyl]benzene (2) PhosphoniumSalt Synthesis

10 g (66 mmol) of S-(+)-1-bromo-2-methylbutane and 17.4 g (66 mmol) oftriphenylphosphine are dissolved in 50 ml of toluene and stirred at 110°C. for 48 hours. The mixture is allowed to warm to room temperature, andthe solid is then filtered off and rinsed with toluene (6.9 g, 25%).

The phosphonium salt (6.9 g, 16.7 mmol) is suspended in 25 ml of driedtetrahydrofuran and cooled to from 0 to 5° C. At this temperature, 8.3ml (16.7 mmol) of 2 M lithium diisopropylamide are added dropwise. After15 minutes, a solution of 3.8 g (16.7 mmol) of 1 in 25 ml of driedtetrahydrofuran is added dropwise. The mixture is allowed to warm toroom temperature and is stirred at this temperature for 1 hour. Water issubsequently added, and the mixture is acidified using 10% HCl andextracted twice with methyl tert-butyl ether. The combined organicphases are washed with water, dried over Na₂SO₄ and filtered, and thesolvent is removed under reduced pressure. The residue is filteredthrough SiO₂ (heptane), (yield: 1.8 g, 22%).

5-Bromo-1,3-difluoro-2-[(R)-3-methylpentyl]benzene (3)

0.4 g of 5% Pt/C (dry) is added to a solution of 1.8 g (5.9 mmol) of 2in 50 ml of heptane, and the mixture is hydrogenated at atmosphericpressure for 20 hours. The solvent is removed under reduced pressure,and the entire amount is converted into 4.

3,5-Difluoro-4-[((R)-3-methylpentyl)phenyl]phenylboronic acid (4)

3.3 ml (5.5 mmol) of 1.6 M BuLi are added dropwise at −78° C. to asolution of 1.4 g (5 mmol) of 3 in 5 ml of dry diethyl ether. After 30minutes, 0.6 ml (5.5 mmol) of trimethyl borate is added dropwise. Themixture is allowed to warm to room temperature overnight. 5.2 ml ofwater, 5.2 ml of methyl tert-butyl ether and 3 ml of conc. HCl aresubsequently added. The organic phase is washed with water (2×3 ml) andsat. NaCl (1×3 ml) and dried using magnesium sulfate, and the solvent isremoved under reduced pressure. The residue is filtered through SiO₂(heptane/dichloromethane 1:1), (yield: 0.8 g, 70%).

EXAMPLE 2 Preparation of the Biphenyl (8)

1,2-Difluoro-3-trimethylsilylbenzene (5)

625 ml (1 mol) of 1.6 M BuLi are added dropwise at −78° C. to a solutionof 114 g (1 mol) of 1,2-difluorobenzene in 1 l of dry tetrahydrofuran.After 1 hour, 140 ml (120 g, 1.1 mol) of trimethylsilyl chloride areslowly added dropwise at −78° C. The mixture is allowed to warm to roomtemperature overnight, and then 200 ml of methyl tert-butyl ether and200 ml of water are added. The organic phase is washed with water (2×100ml) and sat. NaCl (1×100 ml) and dried using magnesium sulfate, and thesolvent is removed under reduced pressure. 170 g (91%) of 5 distil overfrom the residue at from 100 to 102° C./70 mbar.

2-(2,3-Difluoro-4-trimethylsilylphenyl)-5,5-dimethyl-1,3,2-dioxaborinane(6)

625 ml (1 mol) of 1.6 M BuLi are added dropwise at −78° C. to a solutionof 169 g (910 mmol) of 1,2-difluoro-3-trimethylsilylbenzene (5) in 1.41of dry tetrahydrofuran. After 15 minutes, 276 ml (1.2 moi) oftrisopropyl borate are added dropwise. The mixture is allowed to warm toroom temperature overnight. 200 ml of water, 200 ml of methyl tert-butylether and 1.00 ml of conc. HCl are subsequently added. The organic phaseis washed with water (2×100 ml) and sat. NaCl (1×100 ml) and dried usingmagnesium sulfate, and the solvent is removed under reduced pressure.The oily residue is dissolved in 270 ml of THF, and 94 g (910 mmol) ofneopentyl glycol and 455 g of magnesium sulfate are added. After themixture has been stirred for 1 hour, the solvent is removed underreduced pressure, and petroleum ether (273 ml) is added to the oilyresidue. Precipitated neopentyl glycol is removed by filtration. 251 g(87%) of 6 crystallise from the filtrate at −25° C.

(4′-Bromo-2,3,2′-trifluorobiphenyl-4-yl)trimethylsilane (7)

A solution of 16.6 g (120 mmol) of K₂CO₃ in 50 ml of water is added to asolution of 15 g (50 mmol) of 4-bromo-2-fluoro-1-iodobenzene, 14.9 g (50mmol) of 6 and 2.31 g (2 mmol) of [Pd(PPh₃)₄] in 100 ml of dioxane, andthe mixture is refluxed overnight. The organic phase is washed withwater and sat. NaCl, dried over MgSO₄ and filtered through SiO₂. Thesolvent is removed under reduced pressure, petroleum ether is added tothe oily residue, and the product is recrystallised at −25° C. (yield:88%, m.p. 78.0° C.).

Trimethyl(2,3,2′-trifluoro-4′-iodobiphenyl-4-yl)silane (8)

30 ml (48 mmol) of 1.6 M BuLi are added dropwise at −78° C. to asolution of 15.8 g (44 mmol) of 7 in 132 ml of dry THF. After 15minutes, 16 g (57.2 mmol) of 1,2-diiodoethane are added as solid, andthe mixture is allowed to warm to room temperature over the course of 1hour. Water and methyl tert-butyl ether are subsequently added. Theorganic phase is washed with water, sat. Na₂S₂O₅ and sat. NaCl, driedover MgSO₄ and filtered through SiO₂. The solvent is removed underreduced pressure, petroleum ether is added to the oily residue, and theproduct is recrystallised at −25° C. (yield: 84%, m.p. 76.0° C.).

EXAMPLE 3 Preparation of the Terphenyl (10)

Trimethyl-(2,3,2′-trifluoro-4″-propyl-[1,1′,4′,1″]-terphenyl-4-yl)silane(9)

A solution of (2 mmol) of 8, (2.2 mmol) of 4-propylphenylboronic acid,250 mg (2.40 mmol) of neopentyl glycol, 1.53 g (4.84 mmol) of Ba(OH)₂,8H₂O, 1.35 ml (0.103 mmol, 5 mol %) of a 76 mM acetone solution ofPd(OAc)₂ in 20 ml of 95% i-PrOH is stirred at 80° C. for 12 hours. Thesolvent is subsequently removed under reduced pressure. 5 ml of 2 M HClare added to the residue, and the mixture is extracted withdichloromethane (3×5 ml). The combined organic phases are dried overMgSO₄ and filtered through SiO₂. The solvent is removed under reducedpressure, and the residue is converted into 10 (yield: 89%).

2,3,2′-Trifluoro-4-iodo-4″-propyl-[1,1′;4′, 1″]-terphenyl (10)

The total amount of the terphenyl 9 is dissolved in 4 ml of absoluteacetonitrile and reacted with 1.2 ml (6 mmol) of a 5 M solution of ICIin acetonitrile, and the mixture is stirred at room temperature for 1hour. The residue is crystallised at −20° C. for 2 hours. Thesupernatant solution is subsequently sucked off, and the product whichremains is washed with 2 M Na₂S₂O₅ (10 ml) and water (10 ml) and driedin an oil-pump vacuum (yield: 54%).

EXAMPLE 4 Preparation of the Quaterphenyl (11)

3,5,2′,3′,2″-Pentafluoro-4′″-methyl-4-((S)-3-methylpentyl)-[1,4′;1′,1″,1′″]-quaterphenyl(11)

A solution of (0.1 mmol) of 10 (0.12 mmol) of 4, 14 mg (0.13 mmol) ofneopentyl glycol, 95 mg (0.3 mmol) of Ba(OH)₂.8H₂O, 80 μl (6.08 mmol, 5mol %) of a 76 mM acetone solution of Pd(OAc)₂ in 2 ml of 95% i-PrOH isstirred at 80° C. for 12 hours. The solvent is subsequently removedunder reduced pressure. 2 ml of 2 M HCl are added to the residue, andthe mixture is extracted with dichloromethane (3×2 ml). The combinedorganic phases are dried over MgSO₄ and filtered through SiO₂. Thesolvent is removed under reduced pressure, and the residue is purifiedby recrystallisation twice from nonane (yield: 60%).

1% by weight of the quaterphenyl (11) is added to a commerciallyavailable nematic base mixture MLC-6260 from Merck KGaA, Darmstadt, andthe twisting power HTP of the composition is determined by theGrandjean-Cano method at 20° C. The composition has an HTP of −1.9.

EXAMPLE 5 Preparation of the Quaterphenyl (13)

2′,3′,2″-Trifluoro-3,5-dimethyl-4-((S)-3-methylpentyl)-4′″-propyl-[1,4′;1′,1″;4″,1′″]-quaterphenyl(13)

A solution of (0.1 mmol) of 10, (0.12 mmol) of 12, 14 mg (0.13 mmol) ofneopentyl glycol, 95 mg (0.3 mmol) of Ba(OH)₂. 8H₂O, 80 μl (6.08 mmol, 5mol %) of a 76 mM acetone solution of Pd(OAc)₂ in 2 ml of 95% i-PrOH isstirred at 80° C. for 12 hours. The solvent is subsequently removedunder reduced pressure. 2 ml of 2 M HCl are added to the residue, andthe mixture is extracted with dichloromethane (3×2 ml). The combinedorganic phases are dried over MgSO₄ and filtered through SiO₂. Thesolvent is removed under reduced pressure, and the residue is purifiedby recrystallisation twice from nonane (yield: 65%).

1% by weight of the quaterphenyl (13) is added to a commerciallyavailable nematic base mixture MLC-6260 from Merck KGaA, Darmstadt, andthe twisting power HTP of the composition is determined by theGrandjean-Cano method at 20° C. The composition has an HTP of −1.5.

1% by weight of the quaterphenyl (13) is added to a commerciallyavailable nematic base mixture MJ-001667 from Merck KGaA, Darmstadt, andthe twisting power HTP of the composition is determined by theGrandjean-Cano method at 20° C. The composition has an HTP of −1.9.

EXAMPLE 6 Preparation of the Quaterphenyl (15)

2′,3′,2-Trifluoro-3,5-dimethyl-4-((S)-1-methylheptyloxy)-4′″-propyl-[1,4′;1′,1″;4″,1′″]-quaterphenyl(15)

A solution of (0.1 mmol) of 10, (0.12 mmol) of 14, 14 mg (0.13 mmol) ofneopentyl glycol, 95 mg (0.3 mmol) of Ba(OH)₂.8H₂O, 80 μl (6.08 mmol, 5mol %) of a 76 mM acetone solution of Pd(OAc)₂ in 2 ml of 95% i-PrOH isstirred at 80° C. for 12 hours. The solvent is subsequently removedunder reduced pressure. 2 ml of 2 M HCl are added to the residue, andthe mixture is extracted with dichloromethane (3×2 ml). The combinedorganic phases are dried over MgSO₄ and filtered through SiO₂. Thesolvent is removed under reduced pressure, and the residue is purifiedby recrystallisation twice from nonane (yield: 68%).

1% by weight of the quaterphenyl (15) is added to a commerciallyavailable nematic base mixture MLC-6260 from Merck KGaA, Darmstadt, andthe twisting power HTP of the composition is determined by theGrandjean-Cano method at 20° C. The composition has an HTP of −12.1.

1% by weight of the quaterphenyl (15) is added to a commerciallyavailable nematic base mixture MJ-001667 from Merck KGaA, Darmstadt, andthe twisting power HTP of the composition is determined by theGrandjean-Cano method at 20° C. The composition has an HTP of −19.5.

The compounds of the following examples are prepared analogously toExamples 1 to 6 and reaction schemes 1 to 4 using the correspondingstarting compounds:

EXAMPLES 7 TO 21

TABLE 1 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 7 H H H H H H8 H F H H H H C 264 SmE 276 SmA 351 N 355 I 9 H H F H H H C 190 Sm? 210SmC 237 SmA 250 N 335.2 I 10 F F H H H H C 158 SmE 243 SmA 326 I 11 H FF H H H C 197 SmC 218 SmA 300 N 332.5 I 12 H F H F H H C 191 SmC 202 SmA263 N 304.7 I 13 H F H H F H C 239 SmA 322 I 14 H H F F H H C 174 N297.5 I 15 F F H F H H C 145 SmA 270 N 274 I 16 F F H H F H C 190 SmA292 I 17 H F F F H H C 183 N 290.8 I 18 H F F H F H C 177 SmA 282 N300.1 I 19 F F H F F H C 154 SmA 265 N 269 I 20 F F H H F F C 203 SmA249 N 250.6 I 21 H F F F F H C 178 SmC 206 SmA 219 N 284.4 I

EXAMPLES 22 TO 46

TABLE 2 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 22 H H H H HH C 146 Sm? 184 SmC 198 SmA 283 N 336.8 I 23 H F H H H H C 161 SmC 165SmA 293 N 313.7 I 24 H H F H H H C 128 SmC 162 SmA 186 N 297.6 I 25 H HH F H H C 127 N 297.8 I 26 H H H H F H C 152 SmA 227 N 307.0I 27 F F H HH H C 105 Sm? 152 SmA 284 N 287.2 I 28 H F F H H H C 130 SmC (119) SmA232 N 295.5 I 29 H H H F F H 30 H H H H F F C 152 SmA 268 N 274 I 31 H FH H F H C 139 SmA 266 N 283.9 I 32 H F H F H H C 106 SmC 106 SmA 198 N272.1 I 33 H H F H F H C 97 SmC 144 SmA 153 N 264.5 I 34 H H F F H H C120 N 257.7 I 35 F F H F H H C 95 SmA 226 N 245.0 I 36 F F H H F H C 118SmA 243 N 255.7 I 37 H F F F H H C 129 N 251.0 I 38 H F F H F H C 112SmC (110) SmA 211 N 260.1 I 39 H F H H F F C 129 SmA 242 N 251.0 I 40 HH F H F F C 122 SmA 197 N 231.5 I 41 H F H F F H 42 H H F F F H 43 F F HH F F C 158 SmA 206 N 223.7 I 44 F F H F F H 45 H F F H F F C 124 SmA208 N 228.4 I 46 H F F F F H

EXAMPLES 47 TO 71

TABLE 3 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 47 H H H H HH C 186 Sm? 188 N 330.8 I 48 H F H H H H C 144 SmC (141) SmA 251 N 297.9I 49 H H F H H H C 118 N 295.1 I 50 H H H F H H C 112 N 299.7 I 51 H H HH F H C 148 SmA 246 N 299.4 I 52 F F H H H H C 150 SmA 260 N 267.9 I 53H F F H H H C 133 SmA 152 N 287.6 I 54 H H H F F H C 124 SmA 147 N 289.1I 55 H H H H F F C 136 SmA 260 N 264.0 I 56 H F H H F H C 125 SmA 249 N271.8 I 57 H F H F H H C 121 N 264.5 I 58 H H F H F H C 128 N 262.6 I 59H H F F H H C 131 N 267.1 I 60 F F H F H H C 123 SmA 182 N 225.9 I 61 FF H H F H C 152 SmA 240 N 242.0 I 62 H F F F H H C 146 N 256.1 I 63 H FF H F H C 136 SmA 187 N 256.6 I 64 H F H H F F C 151 SmA 243 N 243.0 I65 H H F H F F C 141 SmA 181 N 226.3 I 66 H F H F F H C 129 SmC 174 SmA186 N 257.7 I 67 H H F F F H C 146 N 254.8 I 68 F F H H F F C 191 SmA219 I 69 F F H F F H C 133 SmA 206 N 225.1 I 70 H F F H F F C 145 SmA208 N 224.5 I 71 H F F F F H C 159 N 245.4 I

EXAMPLES 72 TO 86

TABLE 4 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions 72 H H H H H H C 131SmC (113) SmA 186 N 293.6 I 73 H F H H H H C 96 SmA 223 N 270.3 I 74 H HF H H H C 129 N 256.5 I 75 F F H H H H C 117 SmA 226 N 244.4 I 76 H F FH H H C 126 N 254.4 I 77 H F H F H H C 134 N 234.6 I 78 H F H H F H C120 SmA 217 N 250.0 I 79 H H F F H H C 156 N 222.6 I 80 F F H F H H C145 SmA 167 N 209.7 I 81 F F H H F H C 150 SmA 202 N 224.7 I 82 H F F FH H C 155 N 214.8 I 83 H F F H F H C 141 SmA 160 N 242.0 I 84 F F H F FH C 159 SmA 172 N 203.8 I 85 F F H H F F C 190 N 205.0 I 86 H F F F F HC 162 N 214.8 I

EXAMPLES 87 TO 111

TABLE 5 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 87 H H H H HH C 118 N 296.0 I 88 H F H H H H C 98 SmA 197 N 269.1 I 89 H H F H H H C128 N 262.1 I 90 H H H F H H C 134 N 265.1 I 91 H H H H F H C 111 SmA167 N 263.8 I 92 F F H H H H C 109 SmA 222 N 238.6 I 93 H F F H H H C143 N 249.2 I 94 H H H F F H C 139 N 253.0 I 95 H H H H F F C 129 SmA205 N 229.7 I 96 H F H H F H C 120 SmA 205 N 244.1 I 97 H F H F H H C139 N 238.5 I 98 H H F H F H C 136 N 232.1 I 99 H H F F H H C 157 N234.3 I 100 F F H F H H C 149 SmA 160 N 207.8 I 101 F F H H F H C 128SmA 204 N 220.1 I 102 H F F F H H C 162 N 222.2 I 103 H F F H F H C 151N 224.5 I 104 H F H H F F C 134 SmA 204 N 217.1 I 105 H H F H F F C 161N 200.7 I 106 H F H F F H C 152 SmA 148 N 229.0 I 107 H H F F F H C 164N 220.4 I 108 F F H H F F C 170 SmA 190 N 199.2 I 109 F F H F F H C 157SmA 177 N 203.4 I 110 H F F H F F C 169 SmA (158) N 196.9 I 111 H F F FF H C 173 N 212.9 I

EXAMPLES 112 TO 136

TABLE 6 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 112 H H H H HH C 131 N 318.0 I 113 H F H H H H C 97 SmA 227 N 286.1 I 114 H H F H H HC 131 N 281.2 I 115 H H H F H H C 136 N 274.2 I 116 H H H H F H C 109SmA 216 N 280.9 I 117 F F H H H H C 94 SmA 251 N 261.8 I 118 H F F H H HC 130 SmA (113) N 271.8 I 119 H H H F F H C 139 N 276.8 I 120 H H H H FF C 146 SmA 234 N 252.5 I 121 H F H H F H C 114 SmA 233 N 262.8 I 122 HF H F H H C 131 N 233.4 I 123 H H F H F H C 130 N 245.2 I 124 H H F F HH C 160 N 241.8 I 125 F F H F H H C 148 SmA 177 N 214.6 I 126 F F H H FH C 113 SmA 225 N 235.4 I 127 H F F F H H C 149 N 235.7 I 128 H F F H FH C 144 N 242.3 I 129 H F H H F F C 139 SmA 228 N 234.8 I 130 H H F H FF C 152 SmA 176 N 212.6 I 131 H F H F F H C 151 SmA 176 N 250.7 I 132 HH F F F H C 162 N 240.1 I 133 F F H H F F C 152 SmA 208 N 212.6 I 134 FF H F F H C 151 SmA 204 N 223.2 I 135 H F F H F F C 156 SmA 179 N 210.7I 136 H F F F F H C 172 N 235.6 I

EXAMPLES 137 TO 151

TABLE 7 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 137 H H H H HH 138 H F H H H H C 148 SmA 236 N 274.5 I 139 H H H F H H C 132 N 257.8I 140 H H H H F H C 146 SmA 214 N 267.3 I 141 F F H H H H 142 H H H F FH C 138 N 251.2 I 143 H H H H F F C 186 SmA 217 N 236.3 I 144 H F H H FH 145 H F H F H H C 133 SmA 154 N 238.9 I 146 F F H F H H 147 F F H H FH 148 H F H H F F C 154 SmA 198 N 219.5 I 149 H F H F F H C 141 SmA 173N 229.5 I 150 F F H H F F 151 F F H F F H

EXAMPLES 152 TO 176

TABLE 8 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 152 H H H H HH C 150 Sm? (137) N 267.7 I 153 H F H H H H C 153 N 240.5 I 154 H H F HH H C 172 N 240.5 I 155 H H H F H H C 176 N 243.2 I 156 H H H H F H C157 N 214.9 I 157 F F H H H H C 161 SmA 166 N 207.1 I 158 H F F H H H C178 N 232.5 I 159 H H H F F H C 173 N 203.1 I 160 H H H H F F C 160 N203.5 I 161 H F H H F H C 151 N 238.6 I 162 H F H F H H C 174 N 211.1 I163 H H F H F H C 172 N 210.1 I 164 H H F F H H C 196 N 211.0 I 165 F FH F H H C 185 N (181.3) I 166 F F H H F H C 166 SmA 176 N 193.3 I 167 HF F F H H C 193 N 206.0 I 168 H F F H F H C 176 N 198.8 I 169 H F H H FF C 163 SmA 174 N 193.3 I 170 H H F H F F C 182 N (178.5) I 171 H F H FF H C 183 N 208.1 I 172 H H F F F H C 193 N 206.1 I 173 F F H H F F C183 SmA (181) N (182.5) I 174 F F H F F H C 188 N (183.0) I 175 H F F HF F C 183 N (173.1) I 176 H F F F F H

EXAMPLES 177 TO 201

TABLE 9 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 177 H H H H HH C 144 N 281.2 I 178 H F H H H H C 143 SmA 160 N 256.2 I 179 H H F H HH C 164 N 247.3 I 180 H H H F H H C 165 N 249.3 I 181 H H H H F H C 142SmA 174 N 256.2 I 182 F F H H H H C 139 SmA 200 N 226.7 I 183 H F F H HH C 162 N 241.7 I 184 H H H F F H C 169 N 241.2 I 185 H H H H F F C 144SmA 207 N 226.8 I 186 H F H H F H C 150 SmA 194 N 234.7 I 187 H F H F HH C 161 N 222.2 I 188 H H F H F H C 162 N 222.2 I 189 H H F F H H C 182N 216.3 I 190 F F H F H H C 173 N 192.8 I 191 F F H H F H C 154 SmA 193N 209.0 I 192 H F F F H H C 178 N 209.1 I 193 H F F H F H C 169 N 216.8I 194 H F H H F F C 157 SmA 197 N 212.6 I 195 H H F H F F C 169 N 193.7I 196 H F H F F H C 172 N 217.3 I 197 H H F F F H C 179 N 206.1 I 198 FF H H F F C 179 SmA 181 N 192.8 I 199 F F H F F H C 175 N 190.5 I 200 HF F H F F C 176 N 190.4 I 201 H F F F F H C 188 N 201.9 I

EXAMPLES 202 TO 216

TABLE 10 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 202 H H H HH H 203 H F H H H H 204 H H H F H H 205 H H H H F H 206 F F H H H H 207H H H F F H 208 H H H H F F 209 H F H H F H 210 H F H F H H 211 F F H FH H 212 F F H H F H 213 H F H H F F 214 H F H F F H 215 F F H H F F 216F F H F F H

EXAMPLES 217 TO 231

TABLE 11 Example L¹ L² L³ L⁴ L⁵ L⁶ Phase transitions [° C.] 217 H H H HH H C 172 N 249.0 I 218 H F H H H H C 168 N 228.9 I 219 H H H F H H C185 N 216.2 I 220 H H H H F H C 169 N 224.0 I 221 F F H H H H — 222 H HH F F H C 185 N 210.6 I 223 H H H H F F C 174 SmA (165) N 199.1 I 224 HF H H F H C 172 SmA (166) N 210.8 I 225 H F H F H H C 182 N 195.5 I 226F F H F H H C 186 I 227 F F H H F H C 182 SmA 194 N 240.6 I 228 H F H HF F C 181 SmA ? N 190.3 I 229 H F H F F H C 186 N 192.0 I 230 F F H H FF C 194 I 231 F F H F F H C 192 I

EXAMPLES 232 TO 247

TABLE 12 Example R¹ R² Phase transitions [° C.] 232 C₃H₇ C₃H₇ 233 C₃H₇C₄H₉ 234 C₃H₇ C₅H₁₁ 235 C₃H₇ C₆H₁₃ 236 C₄H₉ C₃H₇ C 127 N 263.6 I 237C₄H₉ C₄H₉ C 124 N 251.7 I 238 C₄H₉ C₅H₁₁ 239 C₄H₉ C₆H₁₃ 240 C₅H₁₁ C₃H₇241 C₅H₁₁ C₄H₉ 242 C₅H₁₁ C₅H₁₁ 243 C₅H₁₁ C₆H₁₃ 244 C₆H₁₃ C₃H₇ 245 C₆H₁₃C₄H₉ 246 C₆H₁₃ C₅H₁₁ 247 C₆H₁₃ C₆H₁₃

EXAMPLES 248 TO 272

TABLE 13 Example R¹ R² Phase transitions [° C.] 248 C₃H₇ C₃H₇ 249 C₃H₇t-C₄H₉ 250 C₃H₇ C₅H₁₁ C 99 N 250.6 I 251 C₃H₇ C₆H₁₃ 252 C₃H₇ C₁₀H₂₁ C 93N 207.9 I 253 t-C₄H₉ C₃H₇ 254 t-C₄H₉ t-C₄H₉ 255 t-C₄H₉ C₅H₁₁ C 133 N140.8 I 256 t-C₄H₉ C₆H₁₃ 257 t-C₄H₉ C₁₀H₂₁ C 115 N 119.3 I 258 C₅H₁₁C₃H₇ C 103 N 252.5 I 259 C₅H₁₁ t-C₄H₉ C 134 N 144.3 I 260 C₅H₁₁ C₅H₁₁ C106 N 234.4 I 261 C₅H₁₁ C₆H₁₃ 262 C₅H₁₁ C₁₀H₂₁ C 85 Sm?; N 198.7 I 263C₆H₁₃ C₃H₇ 264 C₆H₁₃ t-C₄H₉ 265 C₆H₁₃ C₅H₁₁ 266 C₆H₁₃ C₆H₁₃ 267 C₆H₁₃C₁₀H₂₁ 268 C₁₀H₂₁ C₃H₇ C 103 SmC 114 N 205.1 I 269 C₁₀H₂₁ t-C₄H₉ C 101SmC 123 N 127.5 I 270 C₁₀H₂₁ C₅H₁₁ C 102 SmC 135 N 197.5 I 271 C₁₀H₂₁C₆H₁₃ 272 C₁₀H₂₁ C₁₀H₂₁ C 104 SmC 158 N 177.3 I

EXAMPLE 273

Phase transitions [° C.]: C 108 SmA 109 N 133.1 l

EXAMPLE 274

Phase transitions [° C.]: C 113 SmA 141 N 204.0 I

EXAMPLE 275

Phase transitions [° C.]: C 127 N

EXAMPLE 276

Phase transitions [° C.]: C 114 SmC 136 l

EXAMPLE 277

Phase transitions [° C.]: C 131 SmA 143 l

EXAMPLE 278

Phase transitions [° C.]: C 138 SmA 244 l

To a liquid-crystalline compound of the following formula:

is added 1% by weight of the compound of Example 278, and the twistingpower HTP of the composition is determined by the Grandjean-Cano methodat 20° C. The composition has an HTP of 3.4.

EXAMPLE 279

Phase transitions [° C.]: C 111 SmA 264 l

To a liquid-crystalline mixture which comprises the following compounds:

is added 1% by weight of the compound of Example 279, and the twistingpower HTP of the composition is determined by the Grandjean-Cano methodat 20° C. The composition has an HTP of 6.3.

EXAMPLE 280

Phase transitions [° C.]: C 108 SmA 216 l

To a liquid-crystalline compound of the following formula:

is added 1% by weight of the compound of Example 280, and the twistingpower HTP of the composition is determined by the Grandjean-Cano methodat 20° C. The composition has an HTP of 6.7.

EXAMPLE 281

Phase transitions [° C.]: C 97 N 190.3 l

To a liquid-crystalline compound of the following formula:

is added 1% by weight of the compound of Example 281, and the twistingpower HTP of the composition is determined by the Grandjean-Cano methodat 20° C. The composition has an HTP of 0.8.

EXAMPLE 282

Phase transitions [° C.]; C 92 N 112 l

To a liquid-crystalline mixture as disclosed in Example 279 is added 1%by weight of the compound of Example 282, and the twisting power HTP ofthe composition is determined by the Grandjean-Cano method at 20° C. Thecomposition has an HTP of 1.3.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1-13. (canceled)
 14. A ring compound of formula XIII:

wherein m and n, independently of one another, are identical ordifferent and are 0 or 1, and the sum (m+n) is 1 or 2, Y is a group offormula XIV

wherein one or two CH groups in the aromatic ring systems may bereplaced by N, X is a single bond, or

L, independently of one another, are identical or different and are R,F, Cl, Br, I, OH, OR, SH, SR, CN, NO₂, NO, CHO, COOH, COOR, CONH₂,CONHR, CONR₂, CF₃, NH₂, NHR or NR₂, R is an alkyl, alkenyl or acyl grouphaving from 1 to 12 carbon atoms or an aryl group having 6 carbon atoms,which is optionally substituted by an alkyl group having from 1 to 12carbon atoms, a, b, c, d, e and f, independently of one another, areidentical or different and are 0, 1 or 2, and the sum (a+b+c+d+e+f) is 1to 8, R¹ and R², independently of one another, are identical ordifferent and are H, F, Cl, CN, NCS, a straight-chain or branched,optionally chiral, alkyl radical or alkoxy radical having from 1 to 12carbon atoms or an alkenyl radical or alkynyl radical having from 2 to 8carbon atoms, in each of which, in addition, one CH₂ group may bereplaced by —O—, —CO—, —O—CO—, —COO— or —CH═CH— in such a way thatheteroatoms are not linked directly to one another and/or one or more Hmay be replaced by halogen, and in the case where m is 0 or n is 0 in R¹or R², one CH₂ group may be replaced by one of the following groups: a)trans-1,4-cyclohexylene, in which, in addition, one or more non-adjacentCH₂ groups may be replaced by —O— and/or —S—, b) a radical from thegroup consisting of 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl,naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and1,2,3,4-tetrahydronaphthalene-2,6-diyl, or c) 1,4-cyclohexenylene, andin which the radicals a), b) and c) are optionally substituted by CN,halogen, or combinations thereof.
 15. A compound according to claim 14,wherein said compound is of formula XVIII

where m and n are each
 1. 16. A compound according to claim 15, whereinR¹ and R², independently of one another, are identical or different andare each C₁-C₇-alkyl.
 17. (canceled)
 18. (canceled)
 19. (canceled) 20.(canceled)
 21. A compound according to claim 14, wherein the sum m+n is2.
 22. A compound according to claim 14, wherein the sum m+n is
 1. 23. Acompound according to claim 22, wherein one CH₂ group in R¹ or R² isreplaced by one of the following groups: a) trans-1,4-cyclohexylene, inwhich, in addition, one or more non-adjacent CH₂ groups may each bereplaced by —O— or —S—, b) a radical from the group consisting of1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl,decahydronaphthalene-2,6-diyl and1,2,3,4-tetrahydronaphthalene-2,6-diyl, or c) 1,4-cyclohexenylene,wherein the radicals a), b) and c) are optionally substituted by CN,halogen, or combinations thereof.
 24. A compound according to claim 14,wherein X is a single bond.
 25. A compound according to claim 14,wherein the sum (a+b+c+d+e+f) is 3 to
 8. 26. A compound according toclaim 14, wherein R¹ and R² are each, independently, H, F, Cl, CN, NCS,a straight-chain or branched, optionally chiral, alkyl radical or alkoxyradical having from 1 to 12 carbon atoms or an alkenyl radical oralkynyl radical having from 2 to 8 carbon atoms, in each of which, inaddition, one CH₂ group may be replaced by —O—, —CO—, —O—CO—, or —COO—in such a way that heteroatoms are not linked directly to one anotherand/or one or more H may be replaced by F.
 27. A compound according toclaim 14, wherein L is in each case, independently of one another, F,Cl, CF₃ or CH₃.
 28. A compound according to claim 14, wherein R² is achiral alkyl radical having from 1 to 12 carbon atoms.
 29. A compoundaccording to claim 15, wherein said compound is of formula XVIIIf orXVIIIg:

where L¹ to L⁶ are each, independently of one another, R, F, Cl, Br, I,OH, OR, SH, SR, CN, NO₂, NO, CHO, COOH, COOR, CONH₂, CONHR, CONR₂, CF₃,NH₂, NHR or NR₂.
 30. A compound according to claim 14, wherein X is


31. A compound according to claim 30, wherein the sum m+n is
 2. 32. Acompound according to claim 14, wherein L is in each case independentlyalkyl, alkenyl or acyl group having from 1 to 12 carbon atoms.
 33. Acompound according to claim 30, wherein L is in each case independentlyalkyl, alkenyl or acyl group having from 1 to 12 carbon atoms.